Today, various types of products have electronic components incorporated therein. Electronic components consume power and generate heat as they operate. The quantity of heat generation may increase depending on the power consumption of the electronic components and density of the placement of the electronic components. Accumulation of heat inside a product housing may raise the temperature inside the housing. Rise of the temperature of a product may cause failure, injury to the user, accidental ignition, or the like. Therefore, when developing a product, design is performed in consideration of countermeasures against heat to improve the reliability and safety of the product.
Here, a heating element such as an electronic component may be air-cooled. Specifically, convection is forcibly generated inside the housing to dissipate heat out of the housing by taking air into the housing of the product or evacuating air from the housing using a fan. In order to examine the performance of heat dissipation by air-cooling, thermo-fluid analysis may be performed using a technique referred to as CFD (Computational Fluid Dynamics). In CFD, a set of basic equations referred to as advection-diffusion equations is used. Evaluation and verification of advection or heat diffusion may be performed by discretizing the space using the difference method, the finite volume method, the finite element method, or the like, and numerically solving the advection-diffusion equations under a condition desired to be verified.
In addition, it is also conceivable to improve the efficiency of cooling by adjusting the operation of the fan. For example, when cooling a part desired to be cooled with a plurality of cooling fans, there is a proposal to control the rotation of the plurality of cooling fans, taking advantage of the cooling capacity of each cooling fan for the part desired to be cooled. In addition, there is a proposal to enhance the evacuation efficiency by setting the rotation speed of some of the plurality of fans which are distant from the outlet of the housing to be higher than the other fans. In addition, there is also a proposal to perform energy saving operation which decreases the rotation speed of the fan in a storage room when an illuminating apparatus is turned off with an aperture of an open showcase being covered with a night cover and the temperature in the storage room of the open showcase is stable.
Japanese Laid-Open Patent Publication No. 2008-235696
Japanese Laid-Open Patent Publication No. 2007-115070
Japanese Laid-Open Patent Publication No. 2010-71609
A plurality of heating elements may be cooled by operating a plurality of fans. On this occasion, when, for example, the temperature of a heating element is lower than the upper limit of the temperature permitted to the heating element, it may be conceivable that the heating element is being over-cooled. In this case, power consumption of the fan may be reduced by reducing the air volume of each fan. However, there arises the problem of how to adjust the air volume of each of the plurality of fans in relation to the temperature of the plurality of heating elements.
For example, although the air volume of the plurality of fans is adjusted focusing on a single heating element, the result of adjustment is not necessarily be appropriate for other heating elements. Other heating elements may be rather over-cooled, or other heating elements may exceed their upper limit temperature. Although it is conceivable to adjust the air volume of each fan with a trial and error approach by performing experiments and simulation while changing the air volume of each fan so that each heating element approaches the upper limit temperature, this method is troublesome and time consuming to determine the air volume of each fan.